Understanding Simulation Logs

Helping you get familiar with simulation and compilation logs and errors
After running a simulation, compiler and simulator logs are available in the Output tab, at the bottom of your screen, next to the Visualizer.

Compiler logs

If everything ran smoothly, you may see some statistics and other informational logs:

Compiler errors

If the model could not be compiled, you might see error logs at the “Compiler” level. In this case, the simulation will not run and no visualizer data will be available.
For instance, if a Data Source block references a file that could not be found in the project, you may get an error like this:
Quite often, these logs will come from the model compiler itself. While the errors can be quite hard to decipher, they will usually carry some information that might help you debug your models.
For instance, if an Adder block’s second input port is not connected, the below error message may appear.
Each message contains a timestamp, the context in which it appeared (Compiler or Simulator), a log level that is one of INFO, WARNING or ERROR, and a human-readable message. Below the message you may see more detailed information about the error itself that might help in debugging the model.

Simulator logs

Once compiled, the model runs as the “Simulator” and can emit various logs. In general, no special message gets emitted, but if the solver failed to converge, some warnings or error messages may appear under Simulator logs.

Simulator errors

In the below example, a CSV file was uploaded for a Data Source block, but it did not contain enough data for the entire simulation:
In the below example, the solver failed to find a solution with a function that diverged towards infinity:
Some of these errors may be “acceptable” errors and the simulation engine will keep running the simulation, but other errors may be “fatal” and the simulation will come to an abrupt end. In both cases, you might expect some invalid results in the Visualizer.